The point of such transfer bids is
that in this siituation, the 1NT bidder is likely to hold the stronger hand;
by having him be the first to name the suit to be played, he will be the
declarer, thus having his hand hidden from the opponents and the weaker
hand becomeing the exposed dummy hand.

Closely related are four-way transfers in which 2S is a transfer to 3C,
and 3C is a transfer to 3D, in addition to the transfers mentioned above,
and Texas transfers, jumps to 4D and 4H which are transfers to the
major suit game bids.